Since your son is over the age of 23 and made over $4050 for the year, you will not qualify to claim him as a dependent. If he files on his own, then Turbo Tax will determine his eligibility to claim earned income credit.
However, you may view the rules for taxpayer's without children at the website below.
https://www.irs.gov/credits-deductions/individuals/earned-income-tax-credit/claiming-eitc-without-a-...
